The present invention relates generally to semiconductor devices and, more particularly, to a method of forming dielectric layers having high dielectric constants.
Various dielectric films are typically required in semiconductor devices. For example, dielectric films are often used as interlayers between conductive layers on the semiconductor device. Some of these dielectric films are required to have a high dielectric constant (K). The high K films are often deposited using conventional chemical vapor deposition (CVD) techniques.
One problem associated with using conventional CVD techniques to deposit high K films is that it is difficult to scale the CVD process to produce thin films having the desired thickness with consistent composition throughout the film. Another problem with conventional CVD techniques is that the resulting dielectric film often does not exhibit good thermal stability throughout the film due to composition control problems.
There exists a need for a method of forming a dielectric layer having consistent composition for improved stability. There also exists a need for a method of forming a dielectric layer that can be easily scaled to achieve the desired thickness.
These and other needs are met by the present invention, where a series of molecular layer (monolayer) depositions may be performed a number of times to produce a dielectric film having the desired K value. The process may also be easily scaled to produce a film having a targeted thickness.
Additional advantages and other features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from the practice of the invention. The advantages and features of the invention may be realized and obtained as particularly pointed out in the appended claims.
According to the present invention, the foregoing and other advantages are achieved in part by a method of forming a dielectric layer on a semiconductor substrate. The method includes transporting the semiconductor substrate to a reaction chamber and providing an oxygen source, a hafnium source and a silicon source to the reaction chamber in a series of separate respective processes. The oxygen, hafnium and silicon sources react to form a plurality of films on the semiconductor substrate, where the films form the dielectric layer.
According to another aspect of the invention, a method of manufacturing a semiconductor device includes providing a wafer having an exposed surface comprising silicon and transporting the semiconductor wafer to a reaction chamber. The method also includes alternately providing an oxygen source and a hafnium source to the reaction chamber in a first series of separate respective processes, where the oxygen source and hafnium source react with the wafer to form a first number of films on the wafer. The method further includes alternately providing a silicon source and an oxygen source to the reaction chamber in a second series of separate respective processes, wherein the silicon source and the oxygen source react to form a second number of films on the wafer.
Other advantages and features of the present invention will become readily apparent to those skilled in this art from the following detailed description. The embodiments shown and described provide illustration of the best mode contemplated for carrying out the invention. The invention is capable of modifications in various obvious respects, all without departing from the invention. Accordingly, the drawings are to be regarded as illustrative in nature, and not as restrictive.